Adjustable crown roll



Filed Jan. 24, 1964 E. J- JUSTUS ADJUSTABLE CROWN ROLL Oct. 4, 19663,276,102

-6 Sheets-Sheet 1 INVENTOR,

Oct. 4, 1966 E. J. JUSTUS ADJUSTABLE CROWN ROLL 6 Sheets-Sheet 2 FiledJan. 24, 1964 I N VENTOR.

E. J. JUSTUS ADJUSTABLE CROWN ROLL Oct. 4, 1966 6 Sheets-Sheet 3INVENTOR.

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Filed Jan. 24, 1964 TTENQNEYS Och 1966 E- J. JUSTUS 3,276,102

I ADJUSTABLE CROWN ROLL Filed Jan. 24, 1964 6 Sheets-Sheet 4 I NVE NTORA TT( )1 Oct. 4, 1966 E. J. JUSTUS I ADJUSTABLE CROWN ROLL 6Sheets-Sheer,

Filed Jan. 24, 1964 I N VENTOR.

BY MZ/M v AT IY RNISYS United States Patent 3,276,102 ADJUSTABLE CROWNROLL Edgar J. Justus, Beloit, Wis., assignor to Beloit Corporation,Beloit, Wis., a corporation of Wisconsin Filed Jan. 24, 1964, Ser. No.339,998 14 Claims. (Cl. 29-116) This application is acontinuation-in-part of application Serial No. 52,456, now Patent No.3,119,324, filed August 29, 1960.

The present invention relates to improvements in rolls and particularlyto an improved roll structure for obtaining controlled nip pressurebetween a roll couple.

In roll couples forming pressure nips therebetween roll deflectionoccurs when loads are applied to the rolls to obtain pressures in thenip. Various arrangements have been employed to obtain either acontrolled or a uniform nip load along the length of the nip, Crownedrolls are usually satisfactory only for one predetermined nip load andother mechanical and hydraulic nip loading devices have not provenentirely satisfactory. The provision of uniform nip pressure isparticularly important in papermakin-g machinery, for example, whereinthe uniform treatment of a web of paper across its width is essential toobtaining a uniform and satisfactory product, and in a Wet press, forexample, uniform extraction of water is dependent upon unifiorm nipload, and in a satisfactory ma chine provisions must be made for varyingthe overall nip load.

An object of the present invention is to provide an improved rollstructure which utilizes a cylindrical rol-l shell supported and loadedon its inner surface by a shoe means opposite the nip which isparticularly satisfactory in obtaining uniform nip pressures over arange of overall nip loads and is capable of continuous high speed longopenating life without rapid Wear and Without requiring frequent partreplacement or servicing attention.

A further object of the invention is to provide an improved rollassembly capable of controlled deflection for obtaining a uniform nipload which is relatively inexpensive to construct and avoidsdisadvantages of the structures heretofore available.

A still further object of the invention is to provide an improved rollassembly having a roll shell with an inner supporting shoe means whereinsuperior lubrication is maintained between the shoe means and the shell,and the provision of extensive fluid seals or close manufacturingtolerances is avoided.

A still further object of the invention is to provide an improvedcontrol deflection roll having an outer roll shell supported on itsinner surface opposite its nip area having features which make itparticularly satisfactory for use in high speed papermaking machines atthe nip loads required and which provides advances over structuresheretofore available that make it practical for commercial use in :suchenvironments.

The mechanism contemplates providing a ro l] assembly including an outerelongate tubular cylindrical roll shell with a non-rotatable shaft meansextending through the shell, means supporting the shaft means, bearingmeans between the roll shell and shaft means for positioning the rollshell, an elongate limber shoe means having an outer surfaceco-extensive with the length of the roll shell and being in axiallycontinuous supporting engagement with the inner surface of the rollshell opposite a nip formed with another roll with said surface beingrigidly shaped to build up a supporting film of lubricating fluid duringrelative notation of the roll shell from fluid within the shell, acontrolled fluid pressure loading means mounted on the shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that 3,276,102 Patented Oct. 4, 1966 a continuous niploading force is maintained within the roll shell, and means pivotallysupporting said shoe means for pivotal movement relative to the innersurfiace of the roll shell to conform to the pressure of the fluidlubricating film between the surface of the shoe means and roll shell.

Other objects, advantages and features of the invention will become moreapparent with the teaching of the principles thereof in connection withthe disclosure of the preferred embodiment in the specification, claimsand drawings, in which: 7

FIGURE 1 is a vertical sectional view taken through the axis of acontrolled deflect-ion 1 011 constructed and operating in accordancewith the principles of the present invention, showing one end of theroll;

FIGURE 2 is a vertical sectional view taken substantially on line IIIIof FIGURE 1;

FIGURE 3 is a smaller sectional view, similar to FIG- URE 1,illustrating the arrangement along the length of the D011;

FIGURE 4 is an enlarged detailed fragmentary view showing the end plateat the end of the fluid pressure channel;

FIGURE 5 is a fragmentary sectional view illustratin the structure ofthe bearing shoe; I

FIGURE 6 is a fragmentary side eleuational view of the pivot bar;

FIGURE 7 is an end elevational view of the pivot bar;

FIGURE 8 is a fragmentary end elevational view showing an arrangementfor two pressure rolls; 7

FIGURE 9 is a fragmentary vertical sectional view showing an arrangementwhereby the controlled deflection roll is driven;

FIGURE 10 is a schematic showing of the fluid pressure circuits andcontrol for the controlled deflection roll;

and

FIGURE 11 is a graph showing pressure relationships for changing nippressures and roll deflection.

As shown on the drawings:

FIGURES 13 show a controlled deflection roll assembly 11 which operatesin a roll couple with a second roll in the manner illustrated in FIGURE8. The roll assembly includes an elongate cylindrical hollow roll shell12 with a core or inner stationary shaft means 13 extendingtherethrough. The roll shell 12 is supported opposite the nip by a shoemeans 14 which slidingly engages the inner surface of the roll shell 12.

The shoe 14 is supported for applying a force to the roll shell by anelongate axially extending piston means or pivot bar 15. The shoe 14 ispivotally supported so as to tiltably conform to the inner surface ofthe shell 12 and the film of supporting lubricating fluid which buildsup between the shoe 14 and inner surface of the shell 12. For providingthe pivotal support an elongate pivot pin 16 is positioned between thepivot bar 15 and the shoe 14.

The inner non-rotatable shaft 13 has a hollow center 17, beingsubstantially tubular in shape within the roll shell 12, and has radialopenings such as 18 for accommodating tubing. At the ends of the shaftare shaft ends 19 which are centrally hollow to accommodate tubing, andbearing lubricating passages 20 extend axially into the shaft ends 19. r

For supporting the roll assembly the shaft is supported at the ends onself-aligning bearings having parts 21 and 22 and a surrounding support23 which is suitably mounted in a bracket such as shown in FIGURE 8. Thebearing parts 21 and 22. are prevented from rotating relatively tothereby hold the shaft 13 against rotation by a threaded pin 24.

In the roll mounting of FIGURE 8, the upper controlled deflection roll11 is supported on a bracket 25 secured to a mounting bracket 26 on amachine frame 27. The controlled deflection roll 11 forms a nip with alower roll 28 which is suitably supported and may be loaded at its endsby suitable mechanism such as that shown schematically by the arrowedline 29 to control the overall nip pressure. An arrangement of this typeprovides a press couple for a wet press of a paper machine and while thefeatures of the invention are particularly well adapted to use in papermachinery for presses, calenders and the like it will be appreciatedthat they may be employed in other environments.

As shown in FIGURE 1, for holding the roll shell 12 in place andmaintaining it in alignment with its mating roll, bearing rings 30 arebolted to the ends of the roll shell and are supported on bearings 31 onthe ends 19 of the shaft. These may be Torrington type bearings securedby a threaded bearing ring 34. Bolted to the bearing ring 35 is an outerring 32 carrying a sheave 33 for driving the roll shell 12 for finishingthe outer surface thereof in preparation for use. The ring 32 has aninwardly extending flange for preventing the escape of lubricant fromthe bearing 31. The lubricant is supplied through the passage 20 andexcess lubricant passes centrifugally out through the passages 35 intothe interior of the roll shell and lubricant deflectors 36 bolted to theend of the shaft 13 clear the ends of the oil passages 35 within theshell so that the oil can escape and be returned through the return lineas will be later described.

As shown in FIGURES 1-3, the inner surface 37 of the roll shell 12 issmooth and the outer surface 38, FIGURES 2 and is formed to a radius 40the same as the radius of the inner surface 37 of the shell 12. Theleading end of the shoe 14 is removed to provide either a curved or, asshown, a flat surface 39 providing a lubricant collecting wedge shapedarea which builds up a film of supporting fluid between the outersurface 38 of the shoe and the inner surface 37 of the shell. Thepivotal support of the shoe 14 permits it to accommodate the building upof this supporting layer of fluid and permits the equalization of thepressure of the fluid over the outer surface 38 of the shoe. With thisarrangement the sliding engagement between the shoe 14 and the shell 12can occur at high speeds required by modern papermaking machinerywithout undue wear and without the generation of undue heat. Thus,because of the rigid outer shape of the shoe with its leading relievednose surface 39, and because of the pivotal support of the shoe 14successful high speed continued support can be achieved.

Another factor which contributes materially to the successfulrelationship between the shoe 14 and shell 12 is the provision of a shoe14 with a continuous elongate outer surface 38 which is co-extensivewith the length of the shell. By providing a continuous outer surface noconcentrations of stress occur and no bending of the shell occurs atunsupported locations. Also there are no nonuniformities along thelength of the shell with respect to the generation of heat due to thefriction and uniform support is maintained along the entire length ofthe nip. The shoe 14 is relatively limber so that it can bend withbending of the roll while maintaining a uniform nip pressure and ispreferably formed of a chilled casting cold worked 35% before machining.While a preferred arrangement is illustrated, it will be understood thatthe shoe could be formed in sections, with each section beingindependent but abutting each other so that the outer surface 38 wouldstill provide a continuous support for the shell. Thus, reference hereinto a continuous supporting surface in an axial direction encompasses thesurface provided by a one-piece limber beam or by a beam formed in anumber of pieces with the pieces closely abutting each other in an axialdirection.

For providing the pivotal support for the shoe 14, an axially extendingarcuate recess 41 is provided on the inner surface of the shoe, and asimilar recess 42, shown in FIGURES 6 and 7, is provided in the pivotbar 15. These recesses 41 and 42 are formed to the radius of the 4 pin16, which may be in sections along its length. The pivot pin is held atthe recesses due to the forces between the pivot bar 15 and the shoe 16.

The pivot bar has a recess 43 extending on all surfaces near its basefor receiving an O-ring to provide a seal for the liquid in an axiallyextending channel 44 in which the pivot bar 15 slides.

The channel 44 is rectangular in shape and is cut for the full length ofthe shaft 13. The channel can easily be milled and its ends are closedby end plates 45. The

inner surfaces of the end plates are relieved at 45a substantially inline with the surface 49 of the core with the relieved portionpreventing the pin 16 from working axially out of the grooves. The endplates are conveniently bolted in place by bolts extending into tappedholes in the shaft.

The shaft 13 is formed with a planar surface 49 on each side of thechannel 44, and the shoe 14 is wider than the width of the channel 44 soas to have surfaces 48 on each side of the channel which seat on theshaft surface 49 when pressure is relieved from the channel 44, butwhich clear the surface 49 during normal operation.

For delivering fluid under pressure to the channel pressure lines 47lead to the channel from a main pressure line 47a.

The channel is shown as formed in sections with dividers 50 between eachof the sections and with the pivot bar 15 similarly formed in sectionsand the sections abutting the dividers 50. The dividers are convenientlyformed by rectangular blocks which are set into the channel and held inplace by bolts tapped into the top of the blocks with a sealing materialaround the edge of the blocks, With this arrangement fluid at differentpressures can be directed to the different compartments into which thechannel is divided by the dividers 50, although usually for maintaininguniform nip pressure the compartments will be interconnected as shown.Fluid pressure is preferably provided by hydraulic oil delivered from acontrolled output pump.

For maintaining lubricating fluid such as oil within the inner surfaceof the shell 12 a lubricating line 51 directs a stream of oil againstthe inner surface of the shell ahead of the shoe 14. This oil spreadsout and provides the built-up layer of lubricating film which formsbetween the shoe and the shell. Excess oil is returned through an oilreturn line 52, FIGURES 1 and 3; for aiding in returning the oil, scoops53 are mounted at the ends of the shaft adjacent the ends of the shoe 14at the leading edge thereof. These scoops gather up the excess oil thatspreads out beyond the end of the shoe and feed it to the return lines52.

Thus, in operation, lubricating fluid is continually supplied to theinner surface of the shell 12 through the lubricating supply line 51,and a film of lubricating oil builds up in the wedge shaped relievedleading edge 39 of the shoe 14 to build up a supporting film between theouter surface 38 of the shoe and the inner surface 37 of the roll shell12. Excess oil is returned through the return lines 52. The shoe 14provides the outer surface 38 which affords continuous supportco-extensive with the roll shell 12.

FIGURE 9 shows an arrangement for continually driving a roll shellduring operation. A roll shell 54 is pro vided with an axially extendingannular end extension 57 that is carried in spaced bearings 60. Theouter race of the bearings 60 is supported in a self-aligning bearing 61which accommodates the bending which will occur without stress.

The bearings 60 also support the load on the inner shaft 55 supportingthe shoe 56. The shaft 55 is supported at its ends on bearings 62a whichare carried in the annular extension 57 which is supported by thebearings 60. The extension is also provided with an end 58 to which adrive sheave is secured.

FIGURE 10 shows schematically a pressure control ar- 'rangement whereinan initial pressure change is made in the force applied to a rollmounted in fixed bearings, and an automatic change is made to thepressure applied to the inner surface of the roll shell. Forces may beapplied to the end of an upper roll 60a by air cylinders 68 at the endsof the roll to control roll bending with air being supplied from anadjustable air pressure valve 62. The valve 62 may be manually operatedor may be automatically controlled in response to other operationalfactors of the machine.

The air pressure signal is supplied to a responsive diaphragm 63 whichsupplies a pressure signal through lines 69 to a diaphragmed pressurebalancing chamber 67. The diaphragm of the chamber 67 is connected to apivotal arm 70 which connects to a diaphragm of a chamber 71. The arm 70is mounted on an adjustable pivot point and the unit including chamber67 and 71 is of the type which is available commercially, such as forexample, a Hagen ratio totalizer. For convenience of reference, thepressure signals are referred to by the letter I, with the initial airpressure signal I being supplied at the diaphragm 63, and transmittedthrough the line 69 to register at I and be converted into a signal IThe signal 1;; is'supplied to a pressure responsive diaphragm 72 whichprovides a signal 1,; to control a by-pass valve 73 that regulates thepressure output of an oil pump 74 receiving, oil from a tank 741:.

The output of the pump 74 is supplied through an oil pressure line 76 toa chamber 77 operating on a piston beneath at loading shoe 78 within aroll shell 61a. The shell 61a forms a nip N with the upper roll 60. Inthe arrangement of FIGURE the loaded roll shell is shown below themating roll 60a and it will be understood that the roll shell may beeither above or below the mating roll and is not limited to a particularposition. The pressure supplied through the line 76 is shown as I and apressure indication signal I is fed from the cylinder 77 to thediaphragm within a pressure chamber 64. The diaphragm acts on a leverarm 65 with its pressure signal I to be converted to a pressure signal Iby acting on a diaphragm Within a pressure chamber 66, connected to thelever arm 65. The diaphragm is loaded by a spring 90 but the resistancepressure of the spring 90 can be altered by a modifying signal providedfrom a valve 79 from a constant air pressure line. By changing the airpressure supply through the valve 79, the relationship between the airpressure and oil pressure can be changed to change the crown of the roll60a. FIGURE 11 shows three curves M M and M which result from threedifferent settings of the valve 79. The unit including chambers 64 and66 can also be a Hagen ratio totalizer or equivalent mechanism.

The output signal 1 is supplied to the upper portion of the chamber assignal I The signal I will thus influence the position of the arm 70 andaccordingly the pressure transmitted to the channel 77. Changes in theslopes of the pressure relationships M M and M can be varied by changingthe location of the pivot point for either the lever arms 65 or 70.

Thus is will be seen that I have provided an improved controlleddeflection roll arrangement which meets the objectives and advantagesabove set forth, and which is capable of obtaining uniform or controllednip pressure avoiding advantages encountered in devices heretoforeavailable.

The drawings and specifications present a detailed disclosure of thepreferred embodiments of the invention, and it is to be understood thatthe invention is not limited to the specific forms disclosed, but coversall modifications, changes and alternative constructions and methodsfalling within the scope of the principles taught by the invention.

I claim as my invention:

1. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

bearing means between the roll shell and shaft for positioninig the rollshell and to maintain it in alignment with the second roll,

a rigid elongate limber shoe means bendable over its length having anouter surface substantially coextensive with the length of the rollshell and being in axially continuous supporting engagement with theinner surface of the shell opposite the nip with said surface beingrigid and of substantially the same radius of curvature as the innersurface of the roll shell and having a leading nose surface spaced fromand facing the oncoming roll shell inner surface to build up asupporting film of lubricating fluid during relative rotation of theroll shell from fluid within the shell,

and a controlled fluid pressure loading means mounted on said shaftmeans applying radially outwardly directed forces to said shoe meansalong the length thereof so that a continuous nip loading force ismaintained within the roll shell independent of bending of the nip withload.

2. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

.bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment With the second roll,

a shoe means having an outer surface axially substantially coextensivewith the roll shell for continuous supporting engagement therewith andhaving a radial outer surface of substantially the same radius ofcurvature as the inner surface of the'roll shell and having a leadingnose'surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell,

means delivering lubricating fluid within the roll shell against theinner surface thereof in advance of said shoe means,

and a controlled fluid pressure loading means mounted on said shaftmeans applying radially outw ardly directed forces to said shoe meansalong the length thereof so that a continuous niploading force ismaintained within the roll shell independent of bending of the nip withload.

3. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

va non-rotatable shaft means extending through said shell,

means supporting said shaft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface substantially co-extensive with thelength of the roll shell and being in axially continuous supportingengagement with the inner surface of the shell opposite the nip,

said surface being arcuate and convex and of substantially the sameradius of curvature as the inner surface of the roll shell and having aleading nose surface spaced from and facing the oncoming roll shellinner surface for building up a supporting film of lubricating fluidbetween the roll shell and shoe means from fluid within the roll shell,

and a controlled fluid pressure loading means mounted on said shaftmeans applying radially outwardly directed forces to said shoe meansalong the length thereof so that a continuous nip loading force ismaintained Within the roll shell independent of bending of the nip withload.

4. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a rigid radial outer surface of substantially the same radius ofcurvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid Within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing channel onsaid shaft means,

a fluid pressure line connected to said channel means,

and an elongate piston means supported by the fluid in said channelmeans supporting said shoe means for applying a radial nip loading forceto said roll shell.

5. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means, bearing means between the roll shelland shaft for positioning the roll shell and to maintain it in alignmentwith the second roll,

a shoe means having an outer surface axially substantially coextensivewith the roll shell for continuous supporting engagement therewith andhaving a rigid radial outer surface of substantially the same radius ofcurvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell, acontrolled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing channel onsaid shaft means,

a fluid pressure line connected to said channel means,

an elongate piston means supported by the fluid in said channel meanssupporting said shoe means for applying a radial nip loading force tosaid roll shell,

and a pivotal connection between said piston means and shoe meanssupporting the shoe means on an axis parallel to the roll shell foraccommodating the film of fluid built up between the inner surface ofthe roll shell and the shoe means.

6. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a rigid radial outer surface of substantially the same radius ofcurvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing channel onsaid shaft means,

a fluid pressure line connected to said channel means,

an elongate piston means supported by the fluid in said channel meanssupporting said shoe means for applying a radial nip loading force tosaid roll shell,

radially facing axially extending recesses in the shoe means and pistonmeans,

and an axially extending pivot pin means in said recesses pivotallysupporting the shoe means for accommodating the film of fluid built upbetween the inner surface of the roll shell and the shoe means.

7. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

21 nLpn-rotatable shaft means extending through said s ell,

means supporting said shaft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a radial outer surface rigidly shaped to build up a supportingfilm of lubricating fluid during relative rotation of the roll s-hellfrom fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing channel onsaid shaft means,

a fluid pressure line connected to said channel means,

an elongate piston means supported by the fluid in said channel meanssupporting said shoe means for applying a radial nip loading force tosaid roll shell,

and a radially outwardly facing shoe support surface on said shaft meansbeside said channel means,

said shoe means being circumferentially wider than the channel andresting on said surface with the collapse of pressure in said channelmeans.

8. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means, bearing means between the roll shelland shaft for positioning the roll shell and to maintain it in alignmentwith the second roll,

a shoe means having an outersurface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a rigid radial outer-surface of substantially the same radius ofcurvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe meansalong thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing channel onsaid shaft means,

a fluid pressure line connected to said channel means,

and a plurality of pistons located in said channel means each supportedby the fluid in said channel means and each supporting said shoe meansfor applying a radial nip loading force to said roll shell.

.9. A roll assembly for forming a pressure nip with a second rollcomprising;

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shalft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewithand-having a rigid radial outer sunface of substantially the same radiusof curvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing channel onsaid shaft means,

a plurality of 'pistons located in said channel means each supported bythe fluid in said channel means and each supporting said shoe means forapplying a radial nip loading force to said roll shell,

rigid dividers in said channel means between said pistons separating thechannel means into a plurality of individual chambers,

and fluid pressure lines connected to the chambers.

10. A roll assembly vfor forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

bearing means between the roll and shaft for positioning the roll shelland to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a radial outer surface rigidly shaped to build up a supportingfilm of lubricating fluid during relative rotation of the roll shellfrom fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

and fluid scoops on the shaft means for removing excess fluid from theinner surface of the roll shell.

11. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a ta 7 dial outer surface rigidly shaped to build up a supportingfilm of lubricating fluid during relative rotation of the roll shellfrom fluid within the shell,

means delivering lubricating fluid within the roll shell against theinner surface thereof in advance of said shoe means,

a controlled fluid pressure loading means mounted on said shaft meansapplying raldially outwardly directed forces to said shoe means alongthe length thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

and a fluid return passage means having an inlet immediately at the endsof said shoe means receiving excess fluid which does not form a filmbetween the shoe means and roll shell.

12. A roll assembly for forming a pressure nip with a second rollcomprising:

an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

means supporting said shaft means,

end bearings between the ends of the roll shell and shaft means,

fluid end scoops on the shaft means projecting for moving fluid from theinner surface of the roll shell,

passages leading from the scoops to said end bearings for lubricatingthe bearings from the scoops,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a radial outer surface rigidly shaped to build up a supportingfilm of lubricating fluid during relative rotation of the roll shellfrom fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

and means pivo-tally supporting said shoe means about an axis parallelto the roll axis for pivotal movement relative to the inner surface ofthe roll to conform to the pressure of the fluid film between the shoemeans and roll shell.

13. A roll assembly for forming a pressure nip with a second rollcomprising:

65 an outer tubular cylindrical roll shell,

a non-rotatable shaft means extending through said shell,

self-aligning bearings supporting each end of the shaft means,

bearing means between the roll shell and shaft for positioning the rollshell and to maintain it in alignment with the second roll,

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewith andhaving a rigid radial outer surface of substantially the same radius ofcurvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

and means pivotally supporting said shoe means about an axis parallel tothe roll axis for pivotal movement relative to the inner surface of theroll to conform to the pressure of the fluid film between the shoe meansand roll shell.

14. A roll assembly for forming a pressure nip with a second rollcomprising:

a shoe means having an outer surface axially substantially co-extensivewith the roll shell for continuous supporting engagement therewtih andhaving a rigid radial outer surface of substantially the same radius ofcurvature as the inner surface of the roll shell and having a leadingnose surface spaced from and facing the oncoming roll shell innersurface to build up a supporting film of lubricating fluid duringrelative rotation of the roll shell from fluid within the shell,

a controlled fluid pressure loading means mounted on said shaft meansapplying radially outwardly directed forces to said shoe means along thelength thereof so that a continuous nip loading force is maintainedwithin the roll shell independent of bending of the nip with load,

means defining an axially elongate radially outwardly facing continuouschannel extending the full length of each shaft means and opening fromthe ends thereof,

plate means on the ends of said channel means,

a fluid pressure line connected to the channel means,

and an elongate piston means supported by the fluid in said channelmeans located between said plate means and supporting the shoe means forapplying a radial nip loading force to said roll shell.

References Cited by the Examiner UNITED STATES PATENTS 242,058 5/ 1881Schurmann 291 16 1,868,860 7/1932 Von Reis. 2,395,915 3/1946 Specht29116 X 2,854,700 11/1958 Caspari et al. 1965 2,960,749 11/ 1960Robertson et al 291 16 X 3,106,153 10/1963 Westbrook 155 3,119,324l/1964 Justus 100170 3,131,625 5/1964 Kusters et al. 100170 LOUIS O.MAASSEL, Primary Examiner.

WALTER A. SCHEEL, Examiner.

1. A ROLL ASSEMBLY FOR FORMING A PRESSURE NIP WITH A SECOND ROLLCOMPRISING: AN OUTER TUBULAR CYLINDRICAL ROLL SHELL, A NON-ROTATABLESHAFT MEANS EXTENDING THROUGH SAID SHELL, MEANS SUPPORTING SAID SHAFTMEANS, BEARING MEANS BETWEEN THE ROLL SHELL AND SHAFT FOR POSITIONINGTHE ROLL SHELL AND TO MAINTAIN IT IN ALIGNMENT WITH THE SECOND ROLL, ARIGID ELONGATE LIMBER SHOE MEANS BENDABLE OVER ITS LENGTH HAVING ANOUTER SURFACE SUBSTANTIALLY COEXTENSIVE WITH THE LENGTH OF THE ROLLSHELL AND BEING IN AXIALLY CONTINUOUS SUPPORTING ENGAGEMENT WITH THEINNER SURFACE OF THE SHELL OPPOSITE THE NIP WITH SAID SURFACE BEINGRIGID AND OF SUBSTANTIALLY THE SAME RADIUS OF CURVATURE AS THE INNERSURFACE OF THE ROLL SHELL AND HAVING A LEADING NOSE SURFACE SPACED FROMAND FACING THE ONCOMING ROLL SHELL INNER SURFACE TO BUILD UP ASUPPORTING FILM OF LUBRICATING FLUID DURING RELATIVE ROTATION OF THEROLL SHELL FROM FLUID WITHIN THE SHELL, AND A CONTROLLED FLUID PRESSURELOADING MEANS MOUNTED ON SAID SHAFT MEANS APPLYING RADIALLY OUTWARDLYDIRECTED FORCES TO SAID SHOE MEANS ALONG THE LENGTH THEREOF SO THAT ACONTINUOUS NIP LEADING LOADING FORCE IS MAINTAINED WITHIN THE ROLL SHELLINDEPENDENT OF BENDING OF THE NIP WITH LOAD.